问题补充：
The girl sings .
A. beautiful, beautiful
B. beautifully, beautifully
C. beautiful, beautifully
D. beautiffully, beautiful
答案：
A. beautiful, beautiful
B. beautifully, beautifully
(答案→)C. beautiful, beautifully
D. beautiffully, beautiful
解析：句意：这个漂亮的女孩歌唱得很好。前面用形容词修饰名词girl，后面用副词修饰动词sing，所有选C。
